The technological developments seen in recent years have facilitated remarkable progress in the field of flexible gastrointestinal (GI) endoscopy. Smaller high-resolution charge-coupled devices (CCDs) have facilitated the manufacture of ultrathin (UT) (<6mm) endoscopes, while the introduction of device assisted enteroscopy (balloon-assisted and spiral enteroscopy) has allowed endoscopists to access the deep small bowel (SB) without the need for recourse to major surgery. Furthermore, the application of double-balloon colonoscopy (DBC) has shown promise to improve outcomes in patients with 'technically difficult' colons. Although these 3 types of innovative endoscopic technologies all share the potential capacity to enhance minimally invasive patient care, research into their optimal role and effectiveness (particularly within UK clinical practice) remains limited. This thesis has examined the potential role of this selection of advanced flexible GI endoscopic technologies for the enhancement of minimally invasive patient care. The first study evaluated transnasal upper GI endoscopy in the UK and confirmed that within this clinical paradigm, transnasal endoscopy using UT endoscopes, is a feasible, effective and more acceptable alternative to patients than conventional oral upper GI endoscopy. The next series of studies were dedicated to device assisted enteroscopy (DBE in particular) and showed that DBE is capable of providing a safe and effective, minimally invasive alternative to major surgery in selected cases. A comparison of spiral enteroscopy as an alternative to DBE, showed that spiral enteroscopy (in its current, manual form), appears to be inferior to DBE in its ability to facilitate deep enteroscopy. The final study evaluated technically difficult colonoscopy and included the development and validation of a score for technical difficulty which may in the future be applied to routine clinical practice. This study also highlighted the usefulness of DBC as a potentially more effective tool than conventional colonoscopy for technically difficult cases.